Typically, terminations of an electrical cable, particularly high voltage outdoor terminations comprises an outer insulator body containing a cable to be terminated. The space between said cable and the interior wall of said outer insulator body being filled with an insulating material which comprises an insulating compound. Said insulating compound can be a liquid or a cross-linking insulating compound which will be described more in detail later. The liquid or cross-linking insulating compound can be filled with an insulating filler, like polyethylene pellets. Said insulating material has a thermally caused expansion, which is receptable since the termination may be exposed to temperatures ranging about 60 to 70 degree between cold winter nights and hot summer days. The increase of volume inside the insulator body requires a free space at the top of the termination. During thermally caused changes of the volume of the insulation compound the excess volume will reduce the free space at the top of the termination and thus compress the trapped air and cause an increase of pressure. Ensuring that said space on top of the termination is maintained free during the installation is rather complicated and requires a special training of the jointers. The problem of proper installation in this particular step is increased in case of conical insulators, which are used to save insulating material in electrical low stress areas close to the top of the termination.
In case said free space (i.e. the space not filled by the insulating material) is too small, a mechanical damage will occur to the insulator body at high temperatures caused by high pressures; in case the space is too large there is a risk of electrical break down because of weaker electrical strength in air than in a liquid or solid material. The general problem to be solved is to increase the quality of the termination and allow for reduction of skill of the jointer, thus leading to a more economical and safer solution.
The invention particularly addresses this problem in order to efficiently simplify the method of building a reliably insulated termination.